Carbapenemase genes in clinical and environmental isolates of Acinetobacter spp. from Quito, Ecuador

Carbapenem-resistant Acinetobacter spp. is associated with nosocomial infections in intensive care unit patients, resulting in high mortality. Although Acinetobacter spp. represent a serious public health problem worldwide, there are a few studies related to the presence of carbapenemases in health care facilities and other environmental settings in Ecuador. The main aim of this study was to characterize the carbapenem-resistant Acinetobacter spp. isolates obtained from four hospitals (52) and from five rivers (27) close to Quito. We used the disc diffusion and EDTA sinergy tests to determine the antimicrobial susceptibility and the production of metallo β-lactamases, respectively. We carried out a multiplex PCR of gyrB gene and the sequencing of partial rpoB gene to bacterial species identification. We performed molecular screening of nine carbapenem-resistant genes (bla_SPM, bla_SIM, bla_GIM, bla_GES, bla_OXA-23, bla_OXA-24, bla_OXA-51, bla_OXA-58, and bla_OXA-143) by multiplex PCR, followed by identification using sequencing of bla_OXA genes. Our findings showed that carbapenem-resistant A. baumannii were the main species found in health care facilities and rivers. Most of the clinical isolates came from respiratory tract samples and harbored bla_OXA-23, bla_OXA-366, bla_OXA-72, bla_OXA-65, bla_OXA-70, and bla_OXA-143-like genes. The river isolates harbored only the bla_OXA-51 and probably bla_OXA-259 genes. We concluded that the most predominant type of carbapenem genes among isolates were both bla_OXA-23 and bla_OXA-65 among A. baumannii clinical isolates.